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Psyche is a NASA Discovery mission designed to rendezvous with a metallic asteroid, 16 Psyche, in the main asteroid belt and study it from orbit. The science goals involve the first exploration of a metal asteroid, with the science objectives of determining: if Psyche is a planetary core, as opposed to unmelted material; the relative ages of Psyche's surface; whether small metal bodies incorporate the same light elements as are expected in the Earth's core; whether Psyche was formed under conditions more oxidizing or reducing than the Earth's core; and the characterization of Psyche's topography. To achieve these objectives, the spacecraft will carry a multispectral imager, gamma-ray and neutron spectrometer, magnetometer, and an X-band gravity investigation.

The Psyche spacecraft bus is box-shaped, 3.1 meters long by 2.4 meters wide. Based on the SSL 1300 satellite bus, it has a dry mass of under 1400 kg. It has two array panels wings, each with 5 solar panels and mounted with a single-axis gimble, which bring the total size of the spacecraft to 24.76 meters by 7.34 meters. A core central cylinder made of graphite composite material makes up the main structural element, and holds seven 82-liter tanks that contain 1064 kg of xenon propellant, protected by thermal blankets. It has a solar electric propulsion system. It will employ the Deep Space Optical Communication technology demonstration to test laser-optical communications, and will also have a 2 meter high-gain X-band dish antenna mounted on the top (+z) deck of the spacecraft. There are also three low-gain antennas. Communications will be via a 100-W Travelling Wave Tube Amplifier (TWTA), allowing uplink of up to 180 kbps. Two booms holding the magnetometers and the Gamma Ray and Neutron Spectrometer also extend from the top surface. A set of four Stationary Plasma Thrusters (SPT-140) are used for spacecraft propulsion. Attitude control and 3-axis stabilization is achieved using four reaction wheels and cold gas thrusters, attitude knowledge is provided by star trackers and a Sun sensor.

Psyche will launch in August 2022 on a Falcon 9 Heavy from Kennedy Space Center. After a Mars gravity assist flyby (within about 500 km) on 24 May 2023, it will reach the asteroid Psyche, and after a 100 day approach phase, during which it will be observing Psyche's rotation and spin axis, it will go into orbit in January 2026. It will study the asteroid from orbit for 21 months. It will initially perform a characterization orbit with a period of 32 hours at a distance roughly 700 km above the surface for 56 days. It will then move down to its topography mapping orbit, at an altitude of about 290 km with a period of 11.25 hours. After 76 days in this orbit, it will drop into a ~170 km altitude gravity mapping orbit with a period of about 6.5 hours. 100 days later it will finish this phase and move down closer to a 4.1 hour elemental mapping orbit with an altitude of roughly 85 km, that will last 100 days. End of mission is scheduled for October 2027.

16 Psyche is an M-type (metallic) asteroid orbiting in the main asteroid belt. The estimated dimensions are 279×232×189 km with an uncertainty of about 10%. The estimated total mass is about 2.7 x 10^19 kg, and density estimates are about 4.5 grams per cubic cm with a large uncertainty. The asteroid appears to be composed primarily of iron and nickel, similar to Earth's core, leading to speculation that it is the remnant core of an ancient planet left after collisions stripped away its rocky outer layers.

Alternate Names

    Facts in Brief

    Launch Date: 
    Launch Vehicle: Falcon 9 Heavy
    Launch Site: Cape Canaveral, United States
    Mass: 1400 kg

    Funding Agency

    • National Aeronautics and Space Administration (United States)


    • Planetary Science

    Additional Information

    Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office



    NameRoleOriginal AffiliationE-mail
    Dr. Linda T. Elkins-TantonMission Principal InvestigatorArizona State
    Dr. Sarah NobleMission ScientistNASA
    Dr. Henry StoneMission ManagerNASA Jet Propulsion
    Dr. Jim BellDeputy Mission Principal InvestigatorArizona State
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